Now, that doesn't make a -lot- of sense, considering when they're first born, they should have no predetermined instinct to 'what is complete' and 'what is not complete.' Baby Marisa should actually get confused once daddy puts on her hat.
Little One, Happy Birthday nano zeIn many case, parent Marisa will catch their newborn child with their hat. This means the babies' first contact with their father is in "incomplete form". So a baby yukkuri recognize their father as "something incomplete + hat".